Process to maintain large clean recreational water bodies

ABSTRACT

The invention discloses a process to implement and maintain large water bodies with color, transparency, and cleanness characteristics similar to swimming pools or tropical seas, at low cost. The present invention also discloses a structure to contain large water bodies, comprising a system for the removal of impurities and surface oils by means of skimmers and a suction device to clean said structure.

This application is a Continuation of U.S. Ser. No. 12/884,872, filed 17Jun. 2010, which is a Continuation of U.S. Ser. No. 11/819,017, filed 25Jun. 2007, which claims benefit of Serial No. 3225-2006, filed 21 Nov.2006 in Chile and which applications are incorporated herein byreference. To the extent appropriate, a claim of priority is made toeach of the above disclosed applications.

FIELD OF THE INVENTION

This invention discloses a process to obtain (i.e., to implement andmaintain) large water bodies or volumes for recreational use, such aslakes or ponds with excellent color, high transparency and cleannesscharacteristics similar to swimming pools or tropical seas at low cost,in particular for water bodies larger than 15,000 m³. The invention alsocomprises a device to extract a particulate material decanted from thewater by using the aforementioned process. Furthermore, the presentinvention discloses a structure to contain large water bodies orvolumes, which is specially designed to carry out said process. Thedecantation process together with the device to extract a decantedmaterial from the water, plus the arrangement of the large volumestructure with its functional characteristics of water surfacedisplacement, allow replacing traditional filtration as used inconventional swimming pools that would be very onerous and inefficientin systems having large bodies or volumes.

BACKGROUND OF THE INVENTION

When a nutrient enters into water, aerobic organisms consume dissolvedoxygen as a result of the induced metabolic activity. Thus, the nutrientexerts a demand on dissolved oxygen availability, which is calledbiological oxygen demand (BOD). If the amount of organic material in themedium is very high, it can lead to a decrease in dissolved oxygenconcentration. At low oxygen levels, aquatic environment promote thegrowth of anaerobic species.

Anaerobic metabolism is much slower than aerobic processes (typicallymore than one order of magnitude) have lower efficiency, and generatesvarious intermediate organic compounds (e.g. organic acids, alcohols,methane). As a result of the lower rate of dissolved organic matterconsumption, this will accumulate in the aquatic environment.

If dissolved oxygen is consumed faster than it can be replenished, waterstarts to deoxygenate. No strictly aerobic organism, from microorganismsto fish, will survive in said water. Thus, organic contaminants willaccumulate and further establish anaerobic conditions, which generatemalodorous substances (e.g. sulfides and volatile amines) and partiallyoxidized organic compounds.

In addition to bad smell, anaerobic conditions can raise human healthissues, because many anaerobic bacteria are pathogenic (for instance,tetanus, and botulism). When the water contains dissolved sulfates,reducing anaerobic bacteria produce H₂S (corrosive and poisonous).

The increase of the amount of nutrients required for life in a waterbody is called eutrophication. Eutrophication is defined as the processof nutrient enrichment in a water body. It is a natural phenomenon inthe ageing process of ponds and lakes (eutrophic lakes). On thecontrary, a young water body, poor in nutrients required for life, iscalled oligotrophic. The nutrient increase in the pond promotes a higherproduction of aquatic plants and animals. Said organic matter increasegenerates in its turn an increase of the organic content of sediments.Eutrophication can generate serious problems in superficial waterbodies.

Photosynthesis implies the creation of organic matter from inorganicmaterials and therefore the production of large amounts of organicsubstances where there were only little amounts before. Whenalgae/plants die, their components are transformed in organic nutrientsthat exert an oxygen demand.

During photosynthetic action, CO₂ is readily consumed, thus producing arise in pH, which can attain a value over 10. During the night, theinverse reaction occurs, consuming oxygen and generating CO₂, with whichpH tends to drop. Photosynthetic activity has a significant effect onthe pH level of the water body, because it affects the reversiblereaction.

HCO³⁻+H+←—→CO₂+H₂O

Finally, the masses of algae deposited in the shore die and rotten, thusproducing anaerobic conditions, which present health dangers (e.g.formation of Clostridium botulinum, a strictly anaerobic pathogenmicroorganism). On the other hand, aquatic plant ramifications retainorganic solids that decompose, which exerts a concentrated oxygendemand.

Generally, nitrogen N and phosphorus P are the limiting factors. Inmicroorganism growth, P is consumed as phosphate, while the major partof bacteria assimilate N under the form of NH₃, and only some of themassimilate N as NO₃ ⁻. Inversely, algae assimilate N as NO₃ ⁻ and veryfew use NH₃. There are more bacteria able to use NO₃ ⁻ as oxygen sourcethan as N source. According to the approximate stoichiometry ofphotosynthesis in algae, N:P ratio is in the order of 7:1. According tothe Liebig minimum law, an N:P ratio much higher than 7 in a water bodyindicates that P is the limiting nutrient; on the other hand, an N:Pratio value much lower than 7 implies an N limitation. Some authorssuggest that P and N concentrations higher than 0.015 and 0.3 mg/l,respectively, are enough to generate an excessive growth of algae inlake waters.

The main sources of organic N are proteins, amino acids and urea; on theother side, inorganic N is in the form of NH₃, NO₃ ⁻, NO₂ ⁻. Ammonia isa characteristic product of organic matter decomposition, and it can bemicrobiologically oxidized to nitrites and nitrates by the action ofnitrifying bacteria. These processes occur naturally in water andconstitute a major contribution to the biological oxygen demand.

When artificial water bodies are formed, such as lakes or ponds, waterquality deteriorates progressively. Depending on the nutrientcontribution, it can be reached any state from equilibrium in whichalgae, aquatic plants, bacteria, insects and fish survive in stablecondition to eutrophication processes in which the excessivecontribution of nutrients produces a high proliferation of algae andaquatic plants. When these die, they are decomposed by bacteria inaerobic processes that consume the oxygen. When oxygen decreases, manyorganic remainders remain deposited in the bottom, thus increasingsediments and suffering processes that increase turbidity, bad smellsare produced and the physicochemical and sanitary quality of the wateris impaired, which reduces the possibilities of recreational use.

To mitigate these effects different techniques are used, such asaeration systems to increase oxygen levels, algaecides and herbicides tocontrol the excessive proliferation of algae and aquatic plants, the useof biological filters to decrease nutrient contribution, fish andzooplancton to reduce algae, nutrient capture by means of chemicals,inoculation of bacteria to digest organic matter, colorants to improvethe aesthetic appearance, mechanic removal of algae and aquatic plants,the use of dredges to decrease the amount of sediment, clarifying agentsto decrease turbidity, etc.

The characteristics and quality of the water of these ponds are verydifferent to those of swimming pools. In the first case, an ecologicalequilibrium between different species must be attained, while in thesecond case the objective is the removal of organisms and impurities.Therefore, very different turbidity, color and physicochemicalcharacteristics standards are accepted.

To keep swimming pool water transparent and apt for bathing, filtrationsystems are used, mainly sand, diatomaceous earth and cartridgefiltration systems. The entire water must be filtered every 4 to 12hours, depending on the type of swimming pool.

In addition, organic matter oxidants, disinfectants, algaecides andeventually pH regulators and clarifiers must be used to keep aestheticand sanitary conditions. Depending on each country's regulation,swimming pools are required to keep minimal disinfectant residualconcentrations or permanent redox potential (ORP) levels between 650 mVand 750 mV.

The application of the swimming pool technology to large water bodies toobtain optimal water quality is not possible due to the high cost of theinstallations and the involved operative costs.

To illustrate this situation, we can recall that if the water body to befiltered is the one described below in the application example of250,000 m³, complying with the minimal regulations of Chilean SwimmingPools (T=2 en NCh 209, example country for the application), 2,983liters per second are required to be filtered, which corresponds to thewater volume treated by a potable water plant for a city. An Olympicswimming pool has 2,500 m³ (50×25×2 m), which corresponds to 1% of theconsidered volume in the application example of this patent application.

The same is true when swimming pools chemicals are to be applied tothese volumes. The water volume of the application example of thisinvention corresponds to 4,000 10-meters-long swimming pools.

The control of disinfectants in swimming pools and spas by means of themeasurement of the (ORP) has been used for many years with good results.ROP measures the oxidizing power of the disinfectant or, in other words,its real concentration-independent chemical activity. Direct measurementof disinfectant concentration can lead to error, because the activitycan be decreased depending on pH and the presence of contaminants, evenat high concentrations. In fact, studies have demonstrated thatbacterial life in water is more dependent on ROP than on oxidantconcentration. To remove undesired microorganisms in swimming pools,normally a ROP value between 650 mV and 750 mV is permanently maintained(public swimming pool regulations in developed countries require morethan 700 mV permanently) at a normal pH between 7.2 and 7.6. This is notpossible with large water bodies due to the high implied costs.

The previously exposed facts make maintaining large water bodies (over15,000 m³) using filtration and disinfection technologies similar tothose of swimming pools for recreational use largely unviable.

Therefore, there are no large artificial ponds or dams with theaesthetic and sanitary characteristics of swimming pools or tropicalseas that have clarity levels higher than 25 and even 40 meters.

The technical problem solved with the present invention is theachievement of these characteristics in large water bodies at low cost.

STATE OF THE ART

Invention patents protecting treatment processes for large volumes ofwater such as ponds and dams were found at world level. In what follows,an analysis of the most relevant documents and their relation with thetechnology to be protected is performed.

Invention patent applications JP4115008 and JP7310311 protect artificialponds connected to the sea that have as objective the purification ofsea water. The system allows the entrance of water to the pond, where itfollows a path specially designed to remove contaminants or it isconducted to a purification facility to be subsequently returned to thesea. Clearly, the Japanese invention has no relation with the type ofpond that is desired to protect in this application.

The invention patent application FR2740493 protects a pool or artificiallake constructed with a flexible bottom comprising a textile net andconcrete. The invention includes a draining system and injectors aroundthe border that allow the diffusion of a liquid to the draining system.The analyzed invention does not have relation with the artificial pondor the process that is to be protected.

The invention patent application JP59222294 protects a purificationprocess for river and lake water to remove N, P, BOD (biological oxygendemand), etc. that implies pumping the water through a bed filled withcertain mineral. The Japanese invention allows cleaning pond water, butbased on water pumping through a packed bed, which is equivalent tofiltering the liquid. Therefore, the Japanese invention does not haverelation with the technology that is to be protected.

The invention patent application CN1256250 protects a water purificationprocess that includes microflocculation with an inorganic flocculantwith high molecular weight and direct deep bed filtration. The analyzedprocess corresponds to an assisted flocculation with faster and moreefficient results, but in no case it affects the novelty or theinventive level of the process of the present invention.

From the analysis of the former documents, it is possible to concludethat there are no processes or artificial ponds similar to those to beprotected, which allow obtaining water bodies larger than 15,000 m³ forrecreational use, with color, transparency and cleanness characteristicssimilar to swimming pools or tropical seas at low cost, because in theprocess of the present invention the traditional filtration step hasbeen substituted by a suspended-solid flocculation step and subsequentcleaning with a suction device, designed for said function, togetherwith the generation of a displacement of surface water that containsimpurities and surface oils by means of injecting inlet water andevacuating said water through skimmers (surface slots and dumps)comprised in the structure, and disinfection has been achieved by theapplication of controlled oxidation pulses.

The present invention is related to a process to obtain large waterbodies or volumes (wherein the term obtaining is meant to be understoodas implementation and maintenance), wherein a structure is provided(having elements required for water treatment and features that producethe desired results) to contain the water, and separation andflocculation (maintenance) processes of particles that make water cloudyand impure are performed, in such a way that flocculated material issuctioned by a suction device once flocculation has taken place, andoily materials are removed through skimmers (surface slots or dumps) ofthe structure of the present invention, said structure having pipes thatfeed fresh water to fulfill the desired objective.

DESCRIPTION OF THE FIGURES

Brief description of the figures.

FIG. 1 shows a side view of the suction device.

FIG. 2 shows a top view of the structure of the suction device.

FIG. 3 a shows a front view of the structure of the suction device.

FIG. 3 b shows a front view of the structure of the suction device.

FIG. 4 a shows a right side view of the suction device.

FIG. 4 b shows a left side view of the suction device.

FIG. 4 c shows a rear view of the suction device.

FIG. 5 a shows a top view of the structure of the suction device.

FIG. 5 b shows a top view of the suction device.

FIG. 6 shows a schematic view of the cleaning system with the suctiondevice.

FIG. 7 shows a detailed schematic view of the suction system with thesuction device.

FIG. 8 shows a schematic view of the suction device.

FIG. 9 shows a schematic view of the structure of the suction device;

FIG. 10 shows a top view of the structure of the water body of thepresent invention.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 shows the following components: moving direction (2) of thesuction device, PVC pipe for suction connection (8), bottom opening (14)in PVC pipe (27) for bottom suction, sanitary T pipe (9), steel frame(10), auto-lubricated plastic wheels (12), supporting plate (19 a) forthe axles of the wheels and rollers (19 b), plastic-based brushes withsynthetic bristles made of polyethylene or the like (20), steel platenwith perforations or slots (21) to fasten the brushes (20) in acontinuous line.

FIG. 2 shows the moving direction (2); the frame (10) to whichsupporting plates (19 a) are affixed to support wheels and rollers axles(19 b) for high density polyurethane rollers (11) that are intercalatedwith wheels (12), which are lined up and also supported by supportingplates (19 a); a brush line (16) fastened to the perforated platen (21)provided with the structure; and the suction line (27) can be observedin the central zone of the device, formed by a PVC tube with fiverectangular bottom openings on wall (14), closed in both ends with a capmade of the same material (17).

In FIGS. 3 a and 3 b the device structure is shown, wherein a supportingplate (1) can be observed for the pulling tensors welded to the frame(10), a resin cover reinforced with fiberglass over a galvanized ironnetwork (6), a lateral plastic membrane flap (7), rollers (11), wheels(12) and sanitary PVC pipes (8) having sanitary T pipes (9) at theirbottom section, and a PVC suction pipe or line (27) attached to the openendings of said T pipes, said suction pipe or line (27) having openingswherein the opening area will be proportional to the installed suctioncapacity.

FIG. 4 a shows a lateral right view of the device with the movingdirection (2), a supporting plate (1) for the pulling tensors, whereasfrom the center a PVC suction pipe (8) emerges having a resin fibercollar attached at its base, said resin fiber collar being formed withfiberglass reinforcements (4) for the fastening and sealing of suctiontubes, handles (5) for pulling, handling and lifting the device, theresin cover (6) and the lateral membrane flap (7). FIG. 4 b shows a leftside view of the device indicating the moving direction (2) and thedevice cover (6). FIG. 4 c shows a rear view of the device indicatingthe device cover (6).

FIG. 5 a shows a top view of the device structure indicating the movingdirection (2) and FIG. 5 b shows a top view of the device indicating themoving direction (2).

FIG. 6 shows the cleaning system with the suction device placed in thewater body (41), wherein there is a pipe to draining chamber (28),plastic buoys (29) for floating a hose (36), platform (30) for thesteersman and the deck operator of the boat (31) for pulling with anincorporated four-stroke engine and protected propeller, a pullingtubular labeled galvanized-steel connecting rod (32) astern, a suctiondevice (33), a connection hose (34) from the boat (31) to the device(33), a connection piece (35) of the connection hose (34) with thesuction hose (36), and a suction hose (36) that connects the movableelectric suction pump (37) at the lake's shore with the boat (31).

FIG. 7 shows a longitudinal section of the suction device in which thepartial configuration of the structural frame (10), the pulling rod (32)that connects the device (33) (not shown in this figure) to the pullingboat, the set of symmetric suction pieces (38) that connect the suctionpipes (27) of the cart with the hose (34) connecting the device to theboat is described. In this figure also appear the projections of wheels(12) and rollers (11).

FIG. 8 shows a lateral view of the pulling boat (31), the suction device(33) placed in the bottom of the water body (41) of the lake, theplacement of the roofed platform (30) for the boat operator, theconnecting rods (32) between the device (33) and the boat (31), thesymmetrical suction elements (38), and the connecting hose (34) withcoupling pipe in the boat (35).

In FIG. 9, a rear view of the system is shown, indicating the connectionhose (34), the pulling rods (32), the set of coupling pieces (38) forsymmetrical suction from all four device inlets toward the connectinghose (34), the hose (36) with floats (29) that connects the boatconnector (35) with the suction pump on land (37), and the pipe thatleads to the drainage (28).

In FIG. 10, the following elements of the structure can be observed:recycle pipe (39) onto which injectors are arranged; injectors (40)arranged along all the perimeter of the water body; water body (41)contained by the structure; skimmers (42) for removal of floatingcontaminants such as water with oils; water inlet line and chamber (43)where water is extracted to feed the lagoon; zone of restricted naturalcirculation (44); fresh water feeding point (45) to the lagoon.

DESCRIPTION OF THE INVENTION

This invention comprises a process to obtain (i.e., to implement andmaintain) large water bodies or volumes for recreational use withexcellent color, high transparency and cleanness characteristics similarto swimming pools or tropical seas at low cost, in particular for waterbodies larger than 15,000 m³, such as artificial ponds or dams forrecreational use. The present invention also discloses a structure tocontain large water volumes. The invention also comprises a suction cartor suction device to extract a particulate material decanted from thewater. The process of the present invention comprises in a first stepproviding a structure to contain large water volumes such as artificiallakes or ponds, with elements that allow water treatment and featuresrequired to obtain the desired aesthetic and sanitary results of having“color, transparency and cleanness similar to swimming pools or tropicalseas at low cost”.

The process has a great advantage over the previous art in that thedesired characteristics are achieved without needing a filtration systemor adding large amounts of chemicals, which opens the possibility toimplement and maintain large crystalline water bodies with no sizelimit.

The process of the invention comprises the following steps or stages:

a.—providing a structure with skimmers able to contain a large waterbody larger than 15,000 m³.

b.—feeding the structure of step (a) with inlet water having iron andmanganese levels lower than 1.5 ppm and turbidity lower than 5 NTU.

c.—measuring water pH, ideally it should be within a range lower than7.8;

d.—adding an oxidizing agent to the water contained in the structure ofstep (a), with which a 600 mV minimal ROP is controlled in water for aminimal period of 4 hours and in maximal cycles of 48 hours;

e.—adding a flocculating agent in concentrations within 0.02 and 1 ppmwith maximal frequencies of 6 days and cleaning the bottom of thestructure of step (a) with a suction device to remove precipitatedimpurities from the bottom of said structure, together with theadditional flocculants and;

f.—generating a displacement of surface water containing impurities andsurface oils by means of the injection of inlet water according to step(b), which generates said displacement in such a way to remove saidsurface water by means of a system for impurities and surface oilsremoval arranged in the structure of step (a).

It is worth mentioning that cleaning is performed in such a way thatevery sector of the structure is cleaned in time intervals no greaterthan 7 days, in such a way as to replace the traditional filteringperformed in conventional size structures.

In the disclosed structure or lake in step (a) it should be maintained aminimal total water renewal rate of 150 days, preferably 60 days, toavoid the accumulation of oxidation products (ageing).

Each step of the process to implement and maintain large water bodies isseparately detailed below, in the understanding that every obviouschange will be encompassed within the scope of the present invention.

In step (a), a structure or pond is provided to contain a large waterbody larger that 15,000 m³, with elements that allow water treatment andfeatures required to obtain the desired aesthetic and sanitary resultsof having “color, transparency and cleanness similar to swimming poolsor tropical seas at low cost”. The features of the structure provided tocarry out steps (b) to (f) of the invention will be noted by the readerwhen the structure specially designed for this invention is specificallydescribed.

In step (b), and only in the case where it should be required, a waterpre-filtering and treatment can be carried out on the water that isincorporated into the lake, in the case wherein the water containsincrusting micro-mollusks or turbidity levels over 5 NTU. Nevertheless,water inlet should not include micro-mollusks and metals such as iron ormagnesium in order to maintain the aforementioned ranges. In otherwords, low turbidity water is preferable because the process of thepresent invention does not have a traditional filtration process and thesuction device and skimmers would be inefficient in case of receivinghigh levels of suspended particles, including both organic and inorganiccontaminants.

If in step (c) the pH is higher than 7.8, it is necessary to add brominesalts such as sodium bromide, always keeping minimal bromideconcentrations of 0.6 ppm. It is worth mentioning that in the case ofsea water, in spite of having pH values higher that 7.8, it naturallycontains high bromide levels, and therefore it is not necessary to addthis element if the artificial pond or lake is filled with sea water.

In step (d), to maintain a minimal redox potential of 600 mV in thewater for a minimal period of 4 hours in maximal cycles of 48 hours,preferably 24 hours, oxidant agents are added such as: ozone, sodium orpotassium persulfate, chlorine derivatives, hydrogen peroxide, brominederivatives or by electrochlorination. The amount of applied oxidant iscontrolled by permanent measurement of ROP during the application insuch a way that it fulfills the minimal established requirements, i.e.oxidant is added up to achieve a minimal of 600 mV during a period of 4hours.

The type of oxidant depends on the cost, among other factors.Hypochlorite produced by electrochlorination and ozone are economicalbecause they are produced in situ, but require high equipmentinvestments.

The applied amount depends on many factors that vary daily, such as, forinstance: temperature, solar radiation, environmental contamination,rain, storms, levels of use, etc. In short, the necessary oxidant amountis determined by ROP measurement.

Notwithstanding the foregoing and without limiting the invention, it canbe stated that the usually used concentrations and the oxidantapplication ranges are those indicated in Table 1:

TABLE 1 Oxidant Application USUAL OXIDANT CONCENTRATION * MIN-MAX RANGEOzone 0.05 ppm 0.01-0.58 ppm Hydrogen peroxide 0.04 ppm 0.01-0.46 ppmSodium hypochlorite 0.16 ppm 0.04-1.50 ppm Persulfate 0.28 ppm 0.07-3.30ppm Bromines 0.22 ppm 0.05-1.80 ppm * Total amount added to reach andmaintain the minimal 600 mV ROP for 4 hours, divided by the total volumeof the water body.

Step (e) includes adding a flocculating agent and cleaning the bottom ofthe structure of step (a) with a suction device in order to removeprecipitated impurities from the bottom of the lake, together with theflocculant agents.

Cleaning is performed in such a way that every sector of the lake iscleaned in time intervals no greater than 7 days, preferably every 4days. With this step, together with the use of skimmers, traditionalfiltering processes used in swimming pools are replaced.

Among flocculants that can be added in this step (e), a cationic polymeris preferred, e.g. HICAT-1™, which is a biodegradable cationicpolyelectrolyte with 25% solids, produced by Buckman Laboratories in theUnited States (it is accepted by the National Health Service of Chileand recommended to be used in swimming pools at concentrations 100 timeshigher) in concentrations between 0.02 and 1 ppm with maximalfrequencies of 6 days, preferably 0.05 ppm every 24 hours; or additionof Crystal Clear™, which is a biodegradable cationic polyelectrolyteproduced by AP Aquarium Products in the United States (it is used inaquariums in concentrations 100 times higher) in concentrations between0.04 and 2 ppm with maximal frequencies of 4 days, preferably 0.16 ppmevery 24 hours.

Additionally, this step can include adding algaecides such as quaternaryammoniums (e.g. polyquats) and/or copper compounds (e.g. CuSO₄·5 H₂O orcopper chelates), keeping copper levels between 1 ppb and 1.5 ppm,depending on temperature and sunlight; 0.3 to 1.5 ppm of copper fortemperature ranges between 10° C. and 30° C.

It is important to keep in mind that the objective of the suction deviceis not only the cleaning of the bottom in the described process, as isthe case of vacuum devices of traditional pools, but that said suctiondevice replaces completely the traditional filtering system of swimmingpools together with the use of flocculants. Furthermore, the fact thatthe process contemplates the displacement and removal of superficialwater with impurities toward the structure slots complements the actionof the suction device.

In other words, the suction device not only removes material naturallydeposited on the bottom (leaves, branches, earth, etc.) but also all thesuspended particles that are eliminated by filtration in the case ofswimming pools and that are converted into floccules (large particles)and are suctioned by the device in this invention, thus decreasing theirremoval costs in two orders of magnitude.

In step (f) it is necessary to control the levels of injection of freshwater to ensure the correct displacement and removal of superficialwater with impurities and oils through the skimmers of the structureprovided in step (a) of the process of the invention.

As hereinabove mentioned, to carry out the process to implement andmaintain large bodies of water larger that 15,000 m³ according to thepresent invention, it is necessary to provide a structure like thatshown as an example in FIG. 10.

The structure or pond according to the present invention includesbottoms and walls built with low permeability materials such as clay andbentonite, coated by a non-porous material, such as a polyvinyl chloridemembrane, lineal low density polyethylene or high density polyethylenecapable of being cleaned, with a depth of at least 0.5 meters, a systemfor removing impurities and superficial oils by means of skimmers, afeeding pipe system that allows water replacement by entrance of freshwater, a feed water intake system, which can be marine water, wellwater, spring water or water from other sources; in the case of marinewater the intake system can be through headers or wells positioned at adepth of more than 6 meters.

The relevance of the structure to solve the technical problem proposedin the process of the present invention is detailed as follows:

The structure must have skimmers to remove surface oils and particles,since otherwise they accumulate and deter water quality, even afterperforming all the chemical treatment steps, since these do not removefloating greases or solids. In this way, the final objective ofobtaining “color, transparency and cleanness characteristics similar toswimming pools or tropical seas at low cost” would not be fulfilledwithout these skimmers. The process of movement of superficial watertoward the skimmers caused by fresh water entry together with theflocculant-suction device system replaces the traditional filteringsystem of swimming pools.

The structure must have fresh water feeding pipes that allow causing thesurface water movement that eliminates floating impurities and oilsthrough the skimmers. These pipes contribute also the fresh waternecessary to refresh water at the described rates, since otherwiseoxidation sub-products accumulate, which render chemical treatmentsinefficient and deter water quality, not fulfilling the “color,transparency and cleanness characteristics similar to swimming pools ortropical seas at low cost”.

The structure has a pipe network with injectors that allow an efficientapplication of the products and water homogenization. In swimming poolsthis is irrelevant, but in large volume water bodies the existence ofisolated stagnant zones creates contamination centers that makedisinfection treatments inefficient, thus deterring water quality andnot fulfilling the fundamental objective of obtaining “color,transparency and cleanness characteristics similar to swimming pools ortropical seas at low cost”.

The plastic liner must have special non-porous characteristics. Inswimming pools this may be irrelevant, but in large volume water bodiescleaning would be unfeasible with adherent linings and a dark layerwould form that do not allow obtaining the desired result, namely“color, transparency and cleanness characteristics similar to swimmingpools or tropical seas at low cost”.

The bottoms and walls must be built with low-permeability materials suchas clay and bentonite, lined with a non-porous material such aspolyvinyl chloride membrane, etc. This is the economic way ofconstructing these large water bodies, since if known buildingtechniques for swimming pools or ponds would be used, the objective of“low cost” would not be obtained.

Water intake must be done in such a way as to avoid micro-mollusks,since besides blocking recycle pipes, said micro-mollusks adhere tosurfaces generating a dark color that prevents obtaining the objectiveof “color, transparency and cleanness characteristics similar toswimming pools or tropical seas at low cost”.

Water intake must avoid water with metals such as iron and manganese,since this pond does not have traditional filtration and theflocculation treatment and suction device are inefficient at removinginorganic impurities, including metallic contaminants.

The crystalline structures or ponds must have water intakes that allowusing low cost water since, in contrast to swimming pools that recyclewater through their filters, in this case the water from the skimmersand the suction cart or device is disposed of.

The structure provided in step (a) for the process of the invention hasadditionally:

1) light blue, white or light yellow bottom (liner) color, for the waterto take the color of tropical seas, i.e. “color, transparency andcleanness characteristics similar to swimming pools or tropical seas atlow cost”. This is obvious in the case of swimming pools, but largeponds use dark plastics due to their durability and lower cost; that isthe reason why there are no large water bodies with the describedcolors. For instance, if the plastic would be black (usual in ponds),the desired color would not be obtained even if the water had highquality and transparency.

2) a depth over 0.5 meters, preferably between 2 and 5 meters; Depth isimportant to achieve the desired color “similar to tropical seas”, sinceif it is too shallow the water does not reach turquoise shades of colorand resembles a light-colored water body. Moreover, due to the highwater transparency of these ponds, if depth is too low UV lightpenetration deters the liner rapidly, thus not obtaining the desired lowcost.

3) a recycling system by means of pipes with injectors that allowmaintaining water homogeneity and avoiding stagnating zones. This systemcan be avoided in windy zones.

4) the structure must be constructed in such a way that it avoidsdragging organic matter such as leaves and soil by effect of wind,watering, etc.

5) Optionally, it can be made of cement with coatings such as painting,poliurethanes or fiberglass.

Therefore, the structure is fundamental for the process of theinvention, since in said structure it is also possible to generate astep consisting of the displacement of surface water containingimpurities and oils by means of a current generated by fresh waterinjection through the pipe systems of said structure, thus removing saidimpurities and oils through said skimmers.

In the following, the suction device of the present invention isdescribed in detail:

The suction device to carry out the cleaning of the structure bottoms,which is performed in step (e) of the process of the invention,comprises: a supporting plate, a resin collar reinforced withfiberglass, pulling handles, a resin cover, a lateral membrane flap, asteel frame, high density polyurethane rollers, auto-lubricated plasticwheels, an opening in a PVC pipe to suction the bottom, a brush linecomprising plastic-based brushes with synthetic bristles and a steelplaten with perforations or slots to fasten the brushes in a continuousline, supporting plates for the axles of the wheels and the rollers, anda suction PVC line with openings (see description of figures for moredetails).

The suction device operates by suctioning dirt through connecting hosesby means of a pumping system, said device being pulled by a system thatincludes a propelling device to move the suction device, such as a boat,for instance, a draining chamber, plastic buoys for aiding a hose tofloat, a platform for the steersman and the boat's deck operator in casea boat is used as propelling device, a pulling tubular labeledgalvanized-steel connecting rod astern, a connection hose between theboat and the cart, a connection piece between the connecting hose andthe suction hose that connects the pump placed at the structure edge. Inany case, the propelling device of the suction device can also be formedby a remote mechanical traction system arranged out of the structure orany other propelling device useful to move the suction device.

The suction device is mainly formed by a structuring frame, a coveringcarcass with coupling means to be coupled to the pumping system, rollingmeans for continuous displacement over the surface to be cleaned andcleaning means consisting of a suction line and a brush line to removethe material to be cleaned by means of suction from the pumping systemthrough the suction device.

The covering carcass comprises a laminar resin body that covers thestructuring frame and the rolling and suction means. From the topsection of the covering carcass supporting plates emerge for the pullingtensors from the boat, which are internally joined to the structuringframe; at its top section, said carcass also has suction PVC tubes thatform coupling means to the pumping system and are attached by their basesection to a carcass collar formed in molded resin fiber with glassfiber reinforcements for supporting and sealing said suction tubes;whereas from said carcass collar a resin mantle and a lateral membraneflap project to form the carcass body. Also its top section has handlesfor pulling, handling and raising the device.

The structuring frame is a steel frame to which an aligned series ofsteel plates for supporting the rolling means, which comprise the axlesof high density polyurethane rollers and plastic auto-lubricated wheels,is supportively joined, and a perforated or slotted steel platen islikewise attached to support by means of bolts a continuous line ofbrushes having a plastic base and synthetic polyethylene bristles, orthe like, which help in the task of removing the material to besuctioned. To the rear section, the abovementioned supporting plates ofthe pulling tensors are joined.

The cleaning means comprise a suction line formed by vertical PVC tubes,corresponding to suction tubes emerging upwardly from the coveringcarcass, to which T-shaped PVC tubes are attached at their bottom part,which are coupled in turn to horizontal tubes that have suction openingsin their bottom part through which the removed material enters to besuctioned and taken out of the pond.

It is important to keep in mind that the objective of the suction device(suction cart) is not only the cleaning of the bottom in the describedprocess, as is the case of vacuum devices of swimming pools, but thatsaid suction device replaces completely the traditional filtering systemof swimming pools together with the use of flocculants and the skimmersystem.

If all the abovementioned elements are not present, water impuritiesaccumulate and deter water quality, and so the final objective of thepresent invention, i.e. obtaining water bodies with “color, transparencyand cleanness characteristics similar to swimming pools or tropicalseas” at low cost, would not be obtained.

APPLICATION EXAMPLE

To carry out the process of the invention to implement and maintainwater bodies larger than 15,000 m³ for recreational use with color,transparency and cleanness characteristics similar to swimming pools ortropical seas at low cost, the following steps or stages were performed:

A structure similar to an artificial lagoon was built in the centralChilean shore, having a length of 1 kilometer, an area of 80,000 m² anda volume of 250,000 m³ (33″20′59.91″S; 71″39′10.10″W). The bottom wasbuilt using clay and bentonite, and it was lined with lineal low densitypolyethylene (LLDPE) and high density polyethylene (HDPE) plastic withwhite and yellow color. The walls were built in cement and clay andlined with LLDPE and HDPE membranes.

Minimal and maximal depths were 1.2 and 3.5 meters, being 2.8 meters theaverage depth.

A pipe system of 100 to 250 mm diameter was installed all around thelagoon borders to facilitate recycling. The system has homogeneouslydistributed injectors every 10 meters around the entire lagoon that areplaced in the bottom to inject the products and maintain waterhomogeneity. Systems for the removal of impurities and superficial oilsby skimmers were installed.

Water intake for this structure was achieved through headers. Inletwater had 0.08 ppm iron and 0.15 ppm manganese, and a turbidity of 1.4NTU. The water had a pH of 7.93 and natural bromine concentrations of 48ppm, and consequently no addition of bromine salts was required. Thewater was impounded through headers at a depth of 8 m at sea shore. Theintake was performed at this depth to avoid incrusting micro-mollusks.The presence of micro-mollusks in sea water causes problems by growing,development and adhesion to piping walls and lagoon structures. Otherpossible way to avoid incrusting micro-mollusks is the use of waterpre-filtering.

ROP value was maintained over 600 millivolts (mV) during 4 hours in24-hour cycles. This was achieved by applying oxidants, such as e.g.ozone, hydrogen peroxide, potassium persulfate, electrochlorination orsodium hypochlorite. All the former were tested with good results.

In an average September day with an air temperature between 10 and 16°C. and a water temperature of 17° C., 0.11 ppm of sodium hypochloriteproduced by electrochlorination were applied, which was sufficient tomaintain ROP over 600 mV for more than 4 hours. This system isadvantageous when working with salt water, because the electrolyticprocess transforms chloride in sea water in hypochlorite, with no needto add additional chemicals.

The established regulations for swimming pools in other countriesindicate higher ROP values (between 650 and 750 mV) permanently, butthis is not economically viable in large volumes of water and in thisinvention it has been demonstrated that keeping ROP over 600 mV during 4hours in 24-hour cycles is enough to decrease the growth of microalgaeand microorganisms in large water bodies, thus generatinglow-contamination conditions apt for swimming.

The bacteria Escherichia coli, a bacterial pathogen marker, dies after100 seconds when exposed to a ROP of 600 mV, and consequently the 4-hourtreatments have a high disinfectant power.

The water body volume of this example equals the volume of 6,000familiar 8-meters-long swimming pools and is constructed in such a waythat it does not receive visible contamination from the surroundings(leaves, soil, watercourses), and consequently contamination receivedfrom the environment is very low in relative terms when compared with aswimming pool. Proportionally, human contamination is also insignificantgiven the high dilution power (for example, 4 swimmers in a familiarpool equal 24,000 swimmers in the lagoon).

Additionally, the flocculation and bottom cleaning with the suctioncart, and the removal of grease and superficial impurities by means ofthe skimmers allows keeping low organic matter levels, which decreasesthe use of oxidants.

Algaecide action was achieved by keeping an average copper level in thewater of around 0.3 ppm, and the application was made by using coppersalts (copper sulfate pentahydrate) in closed sacs, which is applied inthe chambers through which recycling system water passes, in such a waythat the salts dissolve slowly, and also by an copper electrodeionization process in which an electric current is applied to saidelectrodes and copper ions are released into the medium in a controlledway. Measured copper levels varied between 0.1 ppm at a temperature of10° C. and 1.5 ppm at 30° C. (2 ppm are acceptable in potable water, seeTable 4).

A cationic flocculating polymer was added. The flocculant used wasHICAT-1™ in daily applications of 0.04 ppm through the recycling system.

With the aid of the suction cart or device, the plastic of the bottom ofthe lagoon was cleaned subsequently to decantation. The device has asystem of suction chambers, thus removing all the precipitatedimpurities together with the polymer, which allows the bottom of thelagoon (membrane) to be seen. The device that cleaned the plasticmembrane was pulled by a boat and did not leave any residual layer,because it was a fine cleaning and not a dredging. This cleaning andsuction method was permanent and the bottom of the lagoon was cleaneddaily, in such a way that the suction system passes by every membranesector every four days.

The water was maintained in movement by means of a recycling system thatoperated 8 hours per day in low-wind seasons, thus keeping waterhomogeneity. Injectors distributed around the structure throw the waterup to a long distance and are placed every 10 meters. It should bementioned that the water contained by the structure also shows animportant circulation as an effect of the wind and it should be possibleto decrease the artificial recirculation requirements by a suitabledesign of the structure, thus sparing energy.

This recycling system was used to apply chemicals. The water of thestructure was completely renewed in a period between 30 and 150 days.The aim of the renewal was to avoid “water ageing”, which is theformation of secondary compounds derived from oxidation reactions. Therenewal was performed by taking new water through the feeding pipes,independently from the recycling pipes that end at the injectors.

A superficial water outlet flow was kept by means of the skimmers thatremove oils and superficial impurities.

The amount of added chemicals depends mainly on the temperature and isorders of magnitude lower than those required in swimming pools.

The total comparative maintenance cost per cubic meter was approximately3% of the usual cost in swimming pools.

In this application example, the physicochemical conditions of waterwere determined to comply not only with regulations for recreationalwaters with direct contact (see Table 2), which are those applied inthis case, but also with regulations for potable water (see Table 4),with the exception of characteristics inherent to sea water, and withregulations for swimming pools (see Table 3), with the exception ofchlorine permanent residual levels, which do not apply because of theapplied technology.

TABLE 2 Comparison of the water treated with the process of theinvention and the regulation for recreational waters with direct contact(NCh 1333 *) MEASURED VALUE IN THE PARAMETERS LAGOON NCh 1333 pH 7.966.5 to 8.3 except if natural water conditions show diferent values, butin no case lower than 5.0 or higher than 9.0 Temperature, 17.7 30 ° C.,maximal Clarity, minimal * 35 meters Visualization of Secchi discs at adepth of 1.20 meters Visible floating solids Absent Absent and unnaturalfoams Floating oils and <5  5 greases, mg/l, maximal * Emulsified oilsand <5 10 greases, mg/l, maximal * Color, Pc-Co Scale unit, 10 100 maximal * Absent Absence of artificial colors Turbidity, Silica units,0.55 50 maximal * Fecal coliforms/100 ml, <2.0 1,000   maximal *Substances that cause Absent Absent inconvenient smell or taste *Official Chilean regulations were used (Chile was the country of theapplication example), Chilean rule NCh 1333

TABLE 3 Comparison of the water treated with the process of theinvention and the regulation for swimming pools (NCh 209 *) MEASUREDVALUE PARAMETERS IN THE LAGOON NCh 209 pH 7.96 7.2-8.2 Free residualchlorine + 0.5-1.5 (ppm) Copper (algaecides) mg/l 0.38 1.5 maximalBromine (disinfectant) mg/l + 1-3 Foam, grease and Absent Absentsuspended particles Colonies of aerobic 2   ≦200 bacteria/ml Fecalcoliforms Absent Absent Total coliforms ≦2    ≦20 colonies/100 ml Algae,larvae or other Absent Absent living organisms Clarity 35 meters 1.4meters * Official Chilean regulations were used (Chile was the countryof the application example), Chilean rule NCh 209 + Do not apply becauseof the applied technology

TABLE 4 Comparison of the water treated with the process of theinvention and the regulation for potable water (NCh 409 *) MEASUREDOfficial ASSAY VALUE IN THE 2005 NCh PARAMETERS UNIT METHOD LAGOON 409pH — (I) 7.96 6.5 < pH < 8.5 Turbidity NTU (I) 0.55 2.0 True color atPt—Co (I) 10    20   pH = 7.71 Smell — (I) Odorless Odorless Taste —(I) + Tasteless Ammonia mg/l NH₃ (I) 0.12 1.5 Total arsenic mg/l As (I)<0.005   0.01 ⁽¹⁾ Cadmium mg/l Cd (I) <0.002  0.01 Zinc mg/l Zn (I)<0.05  3.0 Total cyanide mg/l CN (I) <0.05   0.05 Chlorides mg/l Cl (I)18,914     400 ⁽²⁾   Copper mg/l Cu (I) 0.38 2.0 Phenolic compounds mg/l(I) <2   2   Total chromium mg/l Cr⁺⁶ (III) <0.05   0.05 Fluorine mg/l F(I) <0.10  1.5 Iron mg/l Fe (I) 0.08 0.3 Magnesium mg/l Mg (I)   1.030 ⁺125    Manganese mg/l Mn (I) <0.01   0.10 Mercury mg/l Hg (I)  0.001 0.001 Nitrates mg/l NO₃ (I) 4.54 50   Nitrites mg/l NO₂ (I) 0.04 3  Lead mg/l Pb (I) <0.02   0.05 Total dissolved mg/l (I)   34.310 ⁺1,500    solids at 105° C. Selenium mg/l Se (I)  0.001  0.01 Sulfatesmg/l SO₄ (I) 2,494 ⁺    500 ⁽²⁾   Free residual chlorine mg/l (III)<0.05  0.2-2.0 in laboratory Nitrate + — (I) <1   1   Nitrite RatioOrganic substance Tetrachloroethene μg/l (*) n.d. 40   Benzene μg/l (*)n.d. 10   Toluene μg/l (*) 0.01 700    Xylenes μg/l (*) n.d. 500   Pesticides D.D.T + D.D.D. + μg/l (*) n.d. 2   D.D.E. 2,4 D μg/l (*) n.d.30   Lindane μg/l (*) n.d. 2   Methoxychlor μg/l (*) n.d. 20  Pentachlorophenol μg/l (*) n.d. 9   Secondary products of disinfectionMonochloramines mg/l (*) <0.1  3   Dibromochloromethane mg/l (*) <0.0050.1 Dichlorobromomethane mg/l (*) n.d.  0.06 Tribromomethane mg/l (*) 0.037 0.1 Trichloromethane mg/l (*) n.d. 0.2 Trihalomethanes mg/l (I)<1   1   MICROBIOLOGICAL ANALYSIS MEASURED Official EXPRESSED ASSAYVALUE IN THE 2005 NCh PARAMETERS AS METHOD POND 409 Total coliformsMPN/100 ml (V) <2.0 <2.0 Escherichia coli MPN/100 ml (V)-(*) ABSENTABSENT n.d. Indicates not detected (*) Official Chilean regulations wereused (Chile was the country of the application example), Chilean ruleNCh 409 ⁺ Inherent values of sea water.

In this example, it has been demonstrated that it is possible tomaintain a water body or volume similar to a large-volume (250,000 m³)artificial sea water pond with a water quality similar to conventionalswimming pools and tropical seas, both in its aesthetic characteristicsas in its physicochemical and bacteriological properties. The achievedcharacteristics have not been found in any existing artificial lagoon inthe world up to date (see Google Earth) and this can be demonstrated bysatellite comparison of the transparency and color of the lagoon to beprotected (33″20′59.91″S; 71″39′10.10″W) with the tens of thousandsexisting in the world, such as golf court and public park lagoons, damsfor recreational use, lagoons of real estate and tourist projects, andeven dams over 15,000 m³ built with swimming purposes (e.g. Piscina doRamos in Brazil, Darwin Swimming Pool in Australia, Orthlieb SwimmingPool in Casablanca, Morocco).

We have not found any artificial water body in the world with a volumehigher than 15,000 m³ having crystalline water with this quality, exceptfor the structure similar to an artificial lagoon that we want toprotect, which has 250,000 m³.

In a Google Earth™ forum (Internet software for satellite photography ofthe world) people has been searching for two years for the biggestswimming pool in the world that can be seen from the air. Theconclusion, when reviewing their results, is that the lagoon of theapplication example is by far the biggest crystalline water body found.

The biggest known swimming pool in the world that uses traditionalfiltering and recycling systems is Sunlite Pool of Coney Island, UnitedStates, having 11,350 cubic meters of water. In the remaining tens ofthousands of large artificial water bodies existing in the world, thewater is not filtered or it is only partially filtered. As previouslymentioned, the characteristics of the water of these bodies are verydifferent from swimming pools or tropical seas and their uses arelimited.

Filtering large water volumes is technically complex and highly costly,and consequently this is a barrier for the scaling-up of crystallinewater bodies. The suction device of the present invention removessuspended solids (turbidity) that flocculate together with the polymerin an efficient and economic way, thus replacing filtering.

In addition to the high costs, the traditional filtering system does notsolve the cleaning of the bottom of the lagoon.

The technology described in this invention patent, i.e. the replacementof filtering by a suction device and skimmers plus the application ofcontrolled oxidation pulses, which are essential parts of the process,allows breaking the barrier that hinders the construction of crystallinelagoons with unlimited extensions and volumes, thus opening a new fieldof tourist applications.

The main advantage of the implemented process is evidenced by comparingthe regulations for recreational waters and the results obtained in theartificial lagoon of the example. Additionally, the level oftransparency obtained in the water is highly important, being theclarity equal or higher than 35 meters, which is a result not found inany water body larger than 15,000 m³ nor in the majority of swimmingpools; in fact, the swimming pool regulation demand only 1.4 meters ofclarity (see Table 3).

Other advantages of the disclosed process of the present invention are:

-   -   Low maintenance costs.    -   Established regulations for recreational waters with direct        contact are widely fulfilled (see Table 2) and comparable        parameters of the swimming pool and potable water regulations        are also fulfilled (see Tables 3 and 4).    -   The water in the lagoon is always absolutely transparent, with        no turbidity, with the characteristic turquoise color of        swimming pools or tropical seas and with a clean bottom, which        are optimal visual characteristics for the acceptation of the        user public.    -   Use of oxidant, algaecide and disinfectant concentrations up to        100 times lower that those recommended to be applied in        conventional swimming pools; this advantage favors the users and        is more environmentally-friendly.    -   As these water bodies are disconnected from the sea or near        natural lakes, they are not affected by temperature variations        produced by oceanographic currents, ice thawing, etc. but only        by environmental variables (temperature, solar radiation, wind).        In practical terms, in the lagoon of the application example in        summer, temperatures of more that 10° C. higher than those of        the sea are obtained.    -   Flocculation and bottom cleaning by suction together with        skimmers replace the filter system of conventional swimming        pools, thus generating high transparency conditions at a very        low cost. The removal of sediments prevents said sediments to        consume oxidants and generate anoxic zones, and they allow the        bottom membrane to give an attractive tonality to the lagoon's        water.    -   Water bodies can be built with no size limit having optimal        aesthetical, physicochemical and sanitary conditions, which        generates large tourist attraction poles.

In order to make more evident the surprising effect of the processdisclosed in the present invention, Table 5 is shown, which illustratethe costs for both cleaning methods in the water body of the applicationexample (250,000 m³).

TABLE 5 Comparison of the traditional filtering method* and the suctiondevice Volume circulated Installation Monthly Specifications throughpumps costs operation costs Traditional 120 15 HP Three-phase 2,893lts/sec US$ 2,686,648⁺ US$ 119,246 filter Aral-C 3000 pumps (Astral code01206) 60 Praga 3000 filters (Astral code 15781) 714,000 kilograms ofsand (Astral code 905000) 60 batteries of 250 mm valves (Astral code19133) Installation labor Shed of 2,500 m² Total monthly energyrequired, 24 hours*30 days*1343.28 kW/hour (967,164.18 kW/hour)Operators Maintenance Suction Windglider boat   10 lts/sec US$ 25,166US$ 2,242 device Protected outboard 9.5 HP motor Suction device Suctionpump 7.5 HP Hoses, accessories Fuel Flocculant Operator Maintenance*Considering T = 2 (minimal rate for swimming pool filtration) accordingto regulation NCh 209 ⁺Does not consider the cost of the land for the2,500 m² shed.

It is important to keep in mind that to obtain the desired final resultof “color, transparency and cleanness characteristics similar toswimming pools or tropical seas at low cost”, it is essential to have awater containing structure that have the required elements for watertreatment and features that allow obtaining the desired results. Theisolated application of the physicochemical process for water treatmentwould not be possible nor would it produce the desired results.

1. A process to obtain a large body of water comprising: a. providing astructure to contain the large body of water; b. treating the waterperiodically to establish oxidation-reduction potential (ORP) within apredetermined range; c. adding an agent to precipitate impurities in thewater to the bottom of the structure; and d. removing the precipitatedimpurities and other suspended debris without filtration of the wholebody of water.
 2. The process of claim 1, wherein providing a structurefurther comprises: providing a: bottom and walls made of lowpermeability materials coated with a non porous material; providing asystem for removing impurities and superficial oils using skimmers;providing a feeding pipe system for introduction of fresh water; andproviding a feed water intake system.
 3. The process of claim 1, whereinthe large body of water is larger than 15,000 m³.
 4. The process ofclaim 1, wherein the large body of water is for recreational use.
 5. Theprocess of claim 1, wherein treating the water to maintainoxidation-reduction potential (ORP) comprises: a. feeding the structurecontaining the large body of water with inlet water having iron andmanganese levels lower than 1.5 ppm and turbidity lower than 5 NTU; b.measuring the water pH; and c. adding an oxidizing agent to the largebody of water to maintain an ORP at a given level in the large body ofwater using a pulse of a given time over a given number of hours in acycle.
 6. The process of claim 5, wherein adding an oxidizing agentcomprises adding an agent to water to maintain an ORP of at least 600 mVin the large body of water using a pulse of at least 4 hours in a 48hour cycle.
 7. The process of claim 5, wherein adding an oxidizing agentcomprises adding an agent to water to maintain an ORP of at least 500 mVin the large body of water using a pulse of at least 4 hours in a 24hour cycle.
 8. The process of claim 1, wherein adding an agent toprecipitate impurities comprises adding a flocculating agent to thelarge body of water contained in the structure.
 9. The process of claim8, wherein the flocculating agent is a cationic polymer added inconcentrations from about 0.02 ppm to about 1 ppm over a time period nogreater than 6 days.
 10. The process of claim 8, wherein theflocculating agent is a cationic polymer added at a concentration of0.05 ppm every 24 hours.
 11. The process of claim 5, wherein brominesalts are added if the pH is higher than 7.8 are added.
 12. The processof claim 11, wherein the bromine salt is sodium bromide, and wherein thebromide concentration is maintained at values higher than 0.6 ppm. 13.The process of claim 5, wherein adding an oxidizing agent comprisesadding an agent from the group consisting of ozone, sodium persulfate,potassium persulfate, chlorine derivatives, hydrogen peroxide, brominederivates, and agents produced by electrochlorination.
 14. The processof claim 5, wherein treating the water to maintain ORP further comprisesadding algaecides to the large body of water.
 15. The process of claim14, wherein the algaecides are selected from the group consisting ofquarternary ammonium salts and copper compounds.
 16. The process ofclaim 15, wherein the copper compounds have copper levels between 1 ppband 1.5 ppm, depending on temperature and sunlight.
 17. The process ofclaim 15, wherein the copper compounds are added at copper levels ofabout 0.3 to about 1.5 ppm for temperatures between 10° C. and 30° C.18. The process of claim 5, wherein feeding the structure with inletwater comprises feeding with inlet water selected from the groupconsisting of sea water, well water, spring water and water from othersources.
 19. The process of claim 1, wherein removing the precipitatedimpurities and other suspended debris without filtration of the wholebody of water further comprises: (a) cleaning the bottom of thestructure containing the large body of water with a movable suctiondevice to remove precipitated impurities; and (b) generating adisplacement of surface water containing impurities and surface oils,comprising injecting inlet water into the large body of water; removingsurface water with the skimmers on the structure containing the largebody of water; and removing suspended debris with a movable suctiondevice, wherein the combination of steps (a) and (b) replace filtrationof the whole body of water.
 20. A process to implement and maintain alarge water body, wherein the process comprises: (a) providing astructure with skimmers able to contain a large water body larger than15,000 m³; (b) feeding the structure of step (a) with inlet water havingiron and manganese levels lower than 1.5 ppm and turbidity lower than 5NTU; (c) measuring water pH, wherein the pH is maintained no lower than5 and no higher than 9; (d) adding an oxidizing agent to the water bodycontained in the structure of step (a), to maintain anoxidation-reduction potential (ORP) of at least 600 mV in the water bodyusing a pulse of at least 4 hours within a 48 hour cycle; (e) adding aflocculating agent in concentrations within 0.02 and 1 ppm over a timeperiod no greater than 6 days to precipitate impurities in the water tothe bottom of the structure of step (a); (f) cleaning the bottom of thestructure of step (a) with a movable suction device to remove theprecipitated impurities from the bottom of said structure, together withthe additional flocculants; and (g) generating a displacement of surfacewater containing impurities and surface oils by means of injection ofinlet water according to step (b), which generates said displacement insuch as way to remove said surface water using said skimmers provided inthe structure of step (a), which together with step (f) replacesfiltration to remove suspended debris from the water body.
 21. Theprocess of claim 20, wherein the large water body is for recreationaluse.